Lahiru Thirimanne's career-best 156 helped Sri Lanka pile on the runs against Northamptonshire on Friday.
Sri Lanka, at lunch on the second day of four at Northampton, were 485 for five in their final match before next week's first Test against England at Lord's.
Sri Lanka were 358 for three overnight. But before play resumed on Friday, opener Kaushal Silva retired on 152 not out with what the Sri Lanka tour manager said was a stomach illness. Silva batted for just over six hours, facing 260 balls with 21 fours and two sixes. Together with Thirimanne, captain in the absence of the rested Angelo Mathews, he'd put on 238 for the fourth wicket. Left-hander Thirimanne resumed on 120 not out, having been dropped first ball Thursday off a regulation chance by wicketkeeper Ben Duckett.
Northamptonshire, struggling at the foot of the First Division of the County Championship table with five defeats from six matches, rested several players from the side that suffered a 271-run thrashing by Yorkshire in their last first-class match.
Among those missing were former South Africa all-rounder Andrew Hall, Pakistani seamer Mohammad Azharullah, New Zealand paceman Ian Butler, and fast bowler Maurice Chambers.
This match did see all-rounder David Willey return to bowling duty but the Northamptonshire left-arm seamer, who sent down 12 overs on Thursday, wasn't called into the attack Friday by home captain Stephen Peters as the county looked to manage his back injury.
Thirimanne was in complete command as he drove a full-toss from medium-pacer Kyle Coetzer down the ground for four. He then surpassed his previous first-class best of 155 not out, made against Bangladesh during a Test in Galle in March last year. But on 156 he was bowled trying to slog-sweep left-arm spinner Matthew Spriegel. Thirimanne batted for nearly five hours facing 221 balls including 14 fours and two sixes.
Spriegel then had a personal return of two wickets for no runs in eight balls, as Sri Lanka's 441 for four became 442 for five, when he bowled Dinesh Chandimal on the sweep for 47.
But Dilruwan Perera, primarily a slow bowler, launched expensive left-arm spinner Graeme White (none for 129) for two sixes. At lunch, Perera was 29 not out and wicketkeeper Prasanna Jayawardene unbeaten on 14.